How to tip a four-piece chimney

Abstract

To provide a four collective chimney falling-down method which can efficiently and safely fall down a four collective chimney.SOLUTION: When the lower part of one chimney 2a is removed, and the lower part of a chimney 2d at a diagonal position of a square in plane view is cut, then a four collective chimney 1 can be simultaneously fallen down to the side of the chimney 2a from which the lower part has been removed with the lower ends of the two remaining chimneys 2b and 2c as supports. In this state, simultaneous fall-down of the four chimneys is started by applying fall-down force capable of falling down the four collective chimney 1 to the side of the chimney 2a from which the lower part has been removed. The fall-down direction is restricted to a direction perpendicular to a straight line connecting the lower ends of the two remaining chimneys 2b and 2c whose upper parts are connected, and accordingly the four collective chimney 1 can be safely and reliably fallen-down in a target direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for overturning a four-piece chimney, and in particular to a method for overturning a four-piece chimney in which the lower ends of four chimneys are arranged at the four corners of a square in plan view and are gathered at the top. [Background technology]

[0002] Patent Document 1 below describes a technique for overturning a chimney to be dismantled during dismantling. This chimney overturning method involves first attaching a hinge mechanism to the lower part of the chimney to be overturned, in an area that will serve as the center of rotation for overturning. The support shaft of the hinge mechanism penetrates the lower part of the chimney in the diametric direction, and face plates supporting the support shaft are fixed on both diametric sides of the outer surface of the lower part of the chimney. The upper part of the chimney is then suspended from above by a crane or similar device, and the chimney is cut and separated into upper and lower halves so that the hinge mechanism can rotate and overturn the chimney. With the separated upper part of the chimney still suspended by the crane, a crane is driven to overturn the upper part of the separated chimney around the support shaft of the hinge mechanism. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 62-268473 Summary of the Invention [Problem to be solved by the invention]

[0004] However, while the chimney toppling method described in Patent Document 1 is effective for a single chimney, it cannot be applied to a group of chimneys, such as those found in thermal power plants. In particular, in a four-piece chimney, where the lower ends of four chimneys are arranged at the four corners of a square in plan view and are joined at the top, it is considered difficult to simultaneously and safely topple the four-piece chimney, even if the bottoms of one or more of the chimneys are removed. Therefore, an efficient and safe method for toppling a four-piece chimney is desired.

[0005] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a method for overturning a four-section chimney that can efficiently and safely overturn a four-section chimney. [Means for solving the problem]

[0006] In order to achieve the above object, the four-section chimney tipping method of the present invention comprises the following steps: A method for overturning a four-piece chimney assembly in which four chimneys arranged at the four corners of a square with their lower ends in a plan view are assembled at the top, The method includes a chimney lower part removal step of removing the lower part of one of the four chimneys from its lower end or from near the lower end to a predetermined height position; a chimney lower part cutting step of cutting the lower part of one chimney located at a diagonal corner of the square of the chimney from which the lower part has been removed to release the connection of the lower part from the installation ground; and a collective chimney tipping step of applying a tipping force to the four chimneys after the chimney lower part cutting step so that they simultaneously tip toward the chimney from which the lower part has been removed, using predetermined positions at the lower ends of the remaining two chimneys as fulcrums.

[0007] With this configuration, if the lower part of one chimney is removed and the chimney located diagonally opposite it in a square plan view is cut at its lower part, the four chimneys can be toppled simultaneously onto the chimney whose lower part was removed, using the lower ends of the remaining two chimneys as fulcrums. In other words, the chimney whose lower part has been removed is no longer supporting any weight, and the chimney diagonally opposite it has also been cut and is no longer connected to the ground, so it can be lifted.

[0008] Therefore, using the lower ends of the remaining two chimneys as a fulcrum, all four chimneys can be toppled simultaneously toward the chimney from which the lower portion has been removed. Then, in this state, a toppling force sufficient to topple the four chimneys is applied to the chimney from which the lower portion has been removed, starting the simultaneous toppling of all four chimneys. The toppling direction is limited to a direction perpendicular to the line connecting the lower ends of the remaining two chimneys whose upper portions are connected, so the four chimneys can be toppled safely and reliably toward the target direction. In other words, this four-piece chimney toppling method allows a four-piece chimney to be toppled efficiently and safely without the need for a hinge mechanism or rotating shaft as described in Patent Document 1.

[0009] Another configuration of the present invention is characterized in that, before the collective chimney toppling process, a reinforcing structure is provided for the lower parts of the remaining two chimneys to prevent buckling when the chimney topples.

[0010] With this configuration, when the chimney falls over, buckling of the two chimneys with reinforced structures is prevented, and the four-piece chimney set can be safely and reliably fallen in the desired direction.

[0011] Another configuration of the present invention is characterized in that the overturning force in the collective chimney overturning process is obtained by applying a load to the chimney from which the lower part of the four-piece collective chimney is to be removed, and gradually increasing the load.

[0012] With this configuration, a downward load is gradually applied to the side of the chimney from which the lower part is removed, i.e., the side on which the four-piece chimney is toppling, so the final toppling force can be obtained while eliminating the problems caused by applying a sudden toppling force, making it possible to topple the four-piece chimney more safely.

[0013] Furthermore, a further configuration of the present invention is characterized in that the overturning force in the collective chimney overturning process is obtained by providing a container capable of containing water in the chimney from which the lower part of the four-piece collective chimney is removed, and gradually increasing the amount of water in the container.

[0014] With this configuration, a downward load is gradually applied to the side of the chimney from which the lower part is removed, i.e., the side on which the four-piece chimney is toppling, so the final toppling force can be obtained while eliminating the problems caused by applying a sudden toppling force, making it possible to topple the four-piece chimney more safely.

[0015] Furthermore, a further configuration of the present invention is characterized in that it includes a tipping force mitigation step of removing a portion of the chimney side where the lower part of the foundation structure connecting the lower ends of the remaining two chimneys to the installation ground is removed before the collective chimney tipping step.

[0016] This configuration makes it possible to reduce the force required for tipping over using the lower ends of the two chimneys as fulcrums. Therefore, by removing a portion of the chimney side where the lower part of the foundation structure of the lower ends of the remaining two chimneys is removed, to the extent that safety is not compromised, tipping over can be made even easier.

[0017] Furthermore, a further configuration of the present invention is characterized by including an alarm issuing step of detecting the downward load fluctuation of the chimney from which the lower part has been removed, and issuing an alarm when the load fluctuation reaches or exceeds a predetermined value.

[0018] With this configuration, the downward load fluctuation of the chimney from which the lower part has been removed, i.e., the load fluctuation in the direction in which the four-piece chimney will tip over, is detected, and an alarm is sounded if the load fluctuation reaches or exceeds a predetermined value, making it possible to prepare for the accidental tipping of the four-piece chimney before the chimney tipping process. [Effects of the Invention]

[0019] As described above, according to the present invention, the two chimneys at the diagonal corners of a square in plan view that have been reinforced can be used as fulcrums to efficiently overturn a four-piece chimney without buckling, thereby shortening the construction period and reducing the cost of dismantling a four-piece chimney. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic explanatory diagram showing one embodiment of a four-piece chimney overturning method of the present invention. FIG. [Figure 2] 2 is an explanatory diagram showing an example of a reinforcement structure in the four-piece chimney overturning method of FIG. 1. FIG. [Figure 3] FIG. 2 is an explanatory diagram showing an example of an alarm issuing process in the four-piece chimney overturning method of FIG. 1. [Figure 4] FIG. 2 is a schematic diagram of a four-piece chimney that is the target of the four-piece chimney overturning method of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0021] An embodiment of the method for overturning a four-piece stack of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic explanatory diagram of the main steps of the method for overturning a four-piece stack of this embodiment, and FIG. 4 is a schematic configuration diagram of the four-piece stack 1 of FIG. 1 that is to be overturned. The four-piece stack 1 to be overturned in this embodiment may be any type as long as it has four stacks 2a-2d gathered at the top, but the lower ends of the four stacks 2a-2d are arranged at the four corners of a square in a plan view. An example of the four-piece stack 1 that is the target of the overturning method of this embodiment is a four-piece stack at a thermal power plant. Because four-piece stacks 1 at thermal power plants are usually erected on the coast, it is efficient to overturn them seaward to avoid interference with other structures. In the following, in this embodiment, the four-piece stack 1 is overturned seaward. Of course, the overturning direction is not limited to the seaward direction if there is reasonable justification for overturning them in another direction. The lower end of each of the chimneys 2a to 2d is fixed to the ground via a foundation structure 3 made of anchor bolts and concrete.

[0022] In this embodiment, to tip the four-piece chimney assembly 1 toward the sea, the lower part of one of the four chimneys 2a to 2d, the sea-side chimney 2a, is removed (chimney lower part removal process). In this process, the lower part of the sea-side chimney 2a is removed within a range of a predetermined height from the lower end or its vicinity. To remove this lower part of the chimney 2a, the entire circumference of the chimney 2a is cut by cutting the lower part with a wire saw or by melting it with a fusion cutter. When removing the lower part of the sea-side chimney 2a, as shown in FIG. 3, the upper part of the chimney 2a in the removal range where the lower part is to be removed is suspended and supported by, for example, a crane truck 5. A load sensor (not shown) is generally provided on the boom 5a of the crane truck 5, and this load sensor detects the downward load fluctuation of the removed chimney 2a. The load fluctuation of the chimney 2a from which the lower part has been removed continues to be detected until the four-piece chimney 1 topples, and when this load fluctuation reaches or exceeds a predetermined value, an alarm is issued indicating that the four-piece chimney 1 is at risk of toppling (alarm issuance process). This makes it possible to prepare for the accidental toppling of the four-piece chimney 1. The alarm may be an audible alarm such as a siren or a visual alarm such as a warning light. Note that instead of using the crane 5 to suspend and support the four-piece chimney 1, a support member made of, for example, a rod-shaped member may be inserted into the removed portion of the chimney 2a from which the lower part has been removed to support the four-piece chimney 1, and the load fluctuation on the toppling side caused by this support member may be detected by a load sensor.

[0023] Prior to this chimney lower part removal process, a reinforcement structure 7 is applied to the lower parts of the remaining three chimneys 2b-2d, excluding chimney 2d, which is one diagonal corner of the square plan view of chimney 2a (seaward), whose lower part will be removed. This applies to the other two chimneys 2b and 2c, i.e., the other two diagonal corners of the square plan view. Figure 2 is a detailed view of the reinforcement structure 7 applied to the lower parts of the other diagonal corners of the square plan view, viewed from the side of chimney 2a, whose lower part will be removed (the removed chimney). This reinforcement structure 7 is formed by fastening chord members 8 made of H-shaped steel between the lowest ends of the two diagonal chimneys 2b and 2c and at a predetermined height therefrom. Diagonal members 9 made of steel angle members are fastened between the upper and lower chord members 8 to form a truss structure. The truss structure is excellent for reinforcing and stiffening, and effectively prevents buckling of the two chimneys 2b and 2c in the direction of chimney extension. This type of reinforcing structure 7 is intended to prevent buckling of the two diagonal chimneys 2b and 2c, which serve as fulcrums for the four-piece chimney 1 to tip over, and it is also possible to adopt reinforcing structures 7 other than those described above.

[0024] When the four-piece chimney 1 is overturned toward the sea side in FIG. 1, the lower part of the chimney 2a from which the lower part has been removed, i.e., the lower part of the chimney 2d on the opposite side of the sea-side chimney 2a, is cut along the entire circumference of the chimney as shown by the two-dot chain line in the arrowed area in FIG. 1 (chimney lower part cutting process). In the case where the lower end of the chimney 2d is connected to the ground (more precisely, to a foundation structure 3 installed on the ground) by a connecting member such as an anchor bolt, this chimney lower part cutting process may also be performed to cut the connection between the chimney 2d and the installation ground by this connecting member along the entire circumference of the chimney. These cuts can be performed using, for example, a wire saw. In other words, the chimney lower part cutting process generally involves cutting the lower part of the chimney 2d diagonally opposite the sea-side chimney 2a to release its connection to the installation ground. In this way, by first removing part of the lower part of the sea-side chimney 2a and then cutting off the lower part of the chimney 2d located diagonally thereto, it is possible to tip the four-piece chimney 1 seaward using the lower ends of the two chimneys 2b and 2c located at the other diagonal corner as fulcrums. As mentioned above, the lower ends of the two chimneys 2b and 2c located at the other diagonal corners are provided with a reinforcing structure 7 consisting of a truss structure that prevents buckling in the chimney extension direction, so the chimneys 2b and 2c, which serve as fulcrums when the chimneys tip over, will not buckle, and the four-piece chimney 1 can be reliably tipped seaward.

[0025] In this case, as shown in FIG. 1 , a container 4, such as a bag capable of containing water, is attached to the tipping side of the four-piece chimney 1, i.e., the chimney 2a from which the lower portion has been removed. Seawater or other water is gradually poured into the container 4 using a pump 6, gradually applying a load to the tipping side of the four-piece chimney 1, thereby applying a tipping force to the four-piece chimney 1 and reliably and safely initiating tipping of the four-piece chimney 1. As described above, in a four-piece chimney 1 in which the lower ends of the chimneys 2a-2d are arranged at the four corners of a square in plan view, even if the lower portions of the two chimneys 2a and 2d located at diagonal corners of the square are removed and cut from the ground, the remaining two chimneys 2b and 2c located at the diagonal corners are still able to stand on their own, making it highly stable. Therefore, the above-described load-increasing method is particularly effective in initiating tipping of the four-piece chimney 1 when the four-piece chimney 1 does not tip automatically even after the chimney lower cutting process is completed. In addition, the method of applying a load to the chimney 2a from which the lower part has been removed and gradually increasing the load to obtain the force to overturn the four-piece chimney 1 can also be achieved, for example, by using heavy machinery to push the four-piece chimney 1 toward the chimney 2a from which the lower part has been removed.

[0026] Furthermore, the foundation structures 3 at the lower ends of the two diagonally positioned chimneys 2b and 2c, which serve as the fulcrums for tipping, may also hinder the spontaneous tipping of the four-piece chimney 1. In such cases, as shown in Figure 1, the foundation structures 3 at the lower ends of the two chimneys 2b and 2c, which serve as the fulcrums for tipping, are removed on the chimney 2a side from which the lower portions have been removed (to be removed), i.e., a portion of the tipping side of the four-piece chimney 1 is removed (tipping force mitigation process). In this way, by removing a portion of the foundation structures 3 at the lower ends of the chimneys 2b and 2c, which serve as the fulcrums for tipping, on the tipping side of the four-piece chimney 1, the support provided by those foundation structures 3 from the tipping side of the four-piece chimney 1 can be removed, and the tipping force applied to the four-piece chimney 1 can be mitigated, allowing the four-piece chimney 1 to tip easily.

[0027] If the four-piece chimney 1 does not automatically tip over even after taking these measures, as shown by the dashed lines in Figure 1, notches 10 may be made in the lower parts of the two diagonally positioned chimneys 2b and 2c that serve as the fulcrum for tipping, on the side of chimney 2a from which the lower part has been removed, i.e., the tipping side of the four-piece chimney 1, and these notches 10 may be used to induce tipping of the four-piece chimney 1. Note that the notches 10, as well as the foundation structure destruction step and tipping initiation step, do not need to be carried out if the four-piece chimney 1 automatically tips over or is about to tip over as a result of the above-mentioned chimney lower part removal step and chimney lower part cutting step.

[0028] In this way, in the method for toppling a four-piece chimney of this embodiment, when the lower part of one chimney 2a is removed and the chimney 2d located diagonally opposite it in a square plan view is cut off at its lower part, the four-piece chimney 1 can be toppled simultaneously onto the chimney 2a whose lower part has been removed, using the lower ends of the remaining two chimneys 2b and 2c as fulcrums. In other words, the chimney 2a whose lower part has been removed is no longer supporting a load, and the chimney 2d located diagonally opposite it has also been cut off and is no longer connected to the ground, so it can be lifted.

[0029] Therefore, it is possible to use the lower ends of the remaining two chimneys 2b and 2c as the fulcrum for tipping, and simultaneously tip the four-piece chimney 1 toward chimney 2a from which the lower part has been removed. Then, in this state, by applying a tipping force sufficient to tip the four-piece chimney 1 toward chimney 2a from which the lower part has been removed, the four chimneys will begin to tip simultaneously. This tipping direction is limited to the direction perpendicular to the line connecting the lower ends of the remaining two chimneys 2b and 2c whose upper parts are connected, so the four-piece chimney 1 can be safely and reliably tip toward the target direction.

[0030] In addition, when the chimney falls over, buckling of the two chimneys 2b and 2c provided with the reinforcing structure 7 is prevented, and the four-piece chimney 1 falls more safely and reliably in the target direction.

[0031] Furthermore, a downward load is gradually applied to the side of the chimney 2a from which the lower part is removed, i.e., the four-piece chimney 1, which is being toppled, so that the final toppling force can be obtained while eliminating the problems caused by applying a sudden toppling force, making it possible to topple the four-piece chimney with greater safety.

[0032] Furthermore, before the collective chimney toppling process, by removing part of the foundation structure 3 that connects the lower ends of the two chimneys 2b and 2c, which serve as the tipping fulcrum, to the installation ground on the side of chimney 2a, the lower part of which is being removed, it is possible to reduce the tipping force required for tipping using the lower ends of the two chimneys 2b and 2c as the fulcrum, making tipping even easier.

[0033] In addition, by detecting the downward load fluctuation of the chimney 2a from which the lower part has been removed, i.e., the load fluctuation in the direction in which the four-piece chimney 1 will tip over, and sounding an alarm if the load fluctuation reaches or exceeds a predetermined value, it becomes possible to prepare for the accidental tipping of the four-piece chimney 1 before the chimney tipping process.

[0034] The above describes a method for overturning a four-piece stack according to an embodiment, but the present invention is not limited to the configurations described in the above embodiment and various modifications are possible within the scope of the present invention. For example, the above embodiment has been described in detail only with respect to the case where a four-piece stack 1 at a thermal power plant is overturned, but the four-piece stack 1 to be overturned is not limited to this. The four-piece stack 1 to be overturned by the tower body overturning method of the present invention can be applied to any four-piece stack 1 as long as the lower ends of the four chimneys 2a to 2d are arranged at the four corners of a square in plan view. [Explanation of symbols]

[0035] 1. Four-piece chimney 2. Chimney 3 Basic structure 4 Containment Unit 5 Crane truck 6. Pump 7 Reinforcement structure

Claims

1. A method for overturning a four-piece chimney assembly in which four chimneys are arranged at the four corners of a square in plan view and the lower ends are gathered at the top, a chimney lower portion removing step of removing a lower portion of one of the four chimneys from its lower end or from a range from the vicinity of the lower end to a predetermined height position; a chimney lower portion cutting process for cutting a lower portion of one chimney located at a diagonal corner of the square of the chimney from which the lower portion has been removed to release the connection of the lower portion from the installation ground; a collective chimney tipping step in which, after the chimney lower portion cutting step, a tipping force is applied to the four chimneys so that the four chimneys simultaneously tip toward the chimney from which the lower portion has been removed, using predetermined positions of the lower ends of the remaining two chimneys as fulcrums; A method for overturning a four-piece chimney, comprising:

2. A method for overturning a four-piece chimney as described in claim 1, characterized in that before the collective chimney overturning step, a reinforcement structure is provided to the lower parts of the remaining two chimneys to prevent buckling when the chimney is overturned.

3. A method for overturning a four-piece chimney as described in claim 1 or 2, characterized in that the overturning force in the collective chimney overturning process is obtained by applying a load to the chimney from which the lower part of the four-piece collective chimney is removed and gradually increasing the load.

4. A method for overturning a four-piece chimney as described in any one of claims 1 to 3, characterized in that the overturning force in the collective chimney overturning process is obtained by providing a container capable of containing water in the chimney from which the lower part of the four-piece collective chimney is removed, and gradually increasing the amount of water in the container.

5. A method for toppling a four-piece chimney assembly described in any one of claims 1 to 4, characterized in that before the collective chimney toppling process, a toppling force mitigation process is provided in which a portion of the chimney side where the lower part of the foundation structure connecting the lower ends of the remaining two chimneys to the installation ground is removed is removed.

6. A method for toppling a four-section chimney as described in any one of claims 1 to 5, characterized in that it includes an alarm issuing process that detects the downward load fluctuation of the chimney from which the lower part has been removed and issues an alarm when the load fluctuation reaches or exceeds a predetermined value.

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